Joining of optical ribbon fiber with connectors is conventionally achieved with multi-fiber ferrules either spring clipped together or incorporated into push-pull connectors and mating the connectors in an adapter. U.S. Pat. No. 5,214,730 shows several versions of spring-clipped ferrules as well as connector and adapter assemblies. Ribbon fiber is gaining wider acceptance in applications that require the ease of connect and disconnect offered by the connector and adapter format as compared to the spring clip format.
The multi-fiber ferrules, in both the spring clip and connector applications, use a pair of guide pin holes flanking the array of fibers and guide pins to align the end faces of the ferrules so that the opposing arrays of fibers are aligned. While the use of guide pin holes and guide pins has proven to align opposing ferrules very precisely, they are extremely tedious and troublesome to use. Initial insertion of the pins into the ferrule faces is painstaking and pins commonly fall out of the ferrules. The drawbacks of the guide pins are heightened even further in the connector and adapter application because the second connector to be inserted is inserted blind and a guide pin and guide pin hole may not line up due to slight variations in adapter and connector dimensions from part to part. Also, connectors are typically connected and disconnected frequently and guide pins may fall out. Another concern with guide pins is that a pair of connectors may be mated with less than both guide pins due to craft inadvertence or lack of training and the fibers would most likely not be aligned. Yet another concern is whether to always have one guide pin per one connector or have two guide pins in half of the connectors and none in the other half. With either option there is potential for guide pins to be transferred from one connector to the other when the connectors are disconnected. This renders that connector out of conformance with whatever guide pin scheme has been adopted. Moreover, in some applications, one of the connectors remains in the adapter and the other side of the adapter receives different connectors. The adapter acts as a shroud to the stationary protector making it impractical to see the status of the guide pins on its end face. Another drawback is the cleaning of the connector end faces. With guide pins in the connector, they must be removed before the end face can be properly cleaned.
Therefore a need exists for a connector and adapter arrangement which takes advantage of the preciseness of the guide pins' alignment yet eliminates the various drawbacks associated with guide pins.